usb: ehci-platform: add support for multiple phys per controller

Added support for cases where one controller is connected
to multiple phys.

Signed-off-by: Arun Ramamurthy <arunrama@broadcom.com>
Reviewed-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Tested-by: Scott Branden <sbranden@broadcom.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>